Interaction of arginine-based cationic surfactants with lipid membranes. An experimental and molecular simulation study

Abstract

The effect of two arginine-based cationic surfactants, arginine N-lauroyl amide dihydrochloride and arginine O-lauroyl ester dihydrochloride, upon dipalmitoylphosphatidylcholine liposomes, is addressed in this work. Some aspects concerning the synthesis of these surfactants are also presented in some detail. Differential scanning calorimetry, as well as fluorescence anisotropy using several probes, is used to assess the relative effects on the lipid model membranes. In spite of the structural similarity among these molecules, which differ only by the group that connects the polar head to the tail, experimental results suggest differences in their behavior. Molecular dynamics simulation provides significant insight into the molecular mechanism that governs this interaction. A rationale is provided in terms of lipid-surfactant hydrogen bonding and the consequent positioning of the surfactant molecule within the bilayer.